\begin{figure}%[htp]
\centering
\subfigure[CPU Usage in Monitor Mode]{\label{fig:cpu-monitor}
    \includegraphics[scale=0.5]{cpu_monitor}}
\subfigure[CPU Usage in Scan Mode]{\label{fig:cpu-scan}
	\includegraphics[scale=0.5]{cpu_scan}}
\subfigure[Comparison of CPU Usage]{\label{fig:cpu-comp}
    \includegraphics[scale=0.5]{cpu}}
\caption{The CPU usage comparison of Monitor and Scan mode}
\label{fig:cpu}
\end{figure}